HOUSTON — The need for more energy, from freeways to battlefields, could be slashed by making fossil-fuel burners more efficient and renewables more dependable, speakers at a conference here said Wednesday.

A prime example cited is the automobile engine. Lawrence Burns, a former General Motors executive who is now director of the program on sustainable mobility at Columbia University, said 75 percent of the energy generated by cars is lost as heat and friction and that much of the remainder is used to move heavy components, leaving enormous potential to boost fuel efficiency.

Only 1 percent of the energy generated by vehicles is used to move drivers, he said.

“I've concluded that we have a system design opportunity, not an energy problem,” Burns said. “When we're wasting 99 percent of the energy we're using to move a person in a car, we're seeing a huge opportunity before us.”

As with other energy uses, a key to major change will involve harnessing emerging technologies. An example is self-driving cars such as those being developed by Google and other companies, he said.

A system of cars that can drive themselves would be more efficient and, with fewer accidents, reduce the need for much of a car's weight, Burns said. He played a GM video of an imagined system in Shanghai involving small vehicles that move smoothly through roads without needing to stop at intersections because they are communicating with each other and moving in concert.

The far-lighter vehicles also make electric-car technology more compelling, he said.

Other opportunities for improved efficiency and energy use are not hard to find, a panel of current and former military officials said.

Soldiers in Afghanistan, for example, rely on a constant stream of batteries to power items including night-vision goggles, GPS units and other tools that cannot be recharged easily in the field, said Col. Peter Newell, director of the U.S. Army's rapid equipping force.

To ensure that equipment does not run low on power, soldiers remove dozens of batteries daily and replace them with new ones pulled directly out of packages, Newell said.

The military is looking to improve energy use, Newell said.

But perhaps one of the greatest opportunities involves wind energy, said Jayshree Desai, executive vice president of Clean Line Energy, which is working to build transmission lines capable of transporting hundreds of megawatts of electricity across half the country.

The goal is to harness abundant wind across the Plains states, “the Saudi Arabia of wind,” Desai said.

“If we could capture that resource ... and get that energy to where people need it,” she said, “then you could really deliver wind at a very low cost and abundant supply.”

She said Clean Line Energy is still years away from building its first of four planned transmission lines because of lengthy permitting and siting processes.

Another major opportunity for maximizing energy availability is storage of surplus power created by renewable sources, an area in which several executives highlighted progress.

Electric-grid improvements that would allow for better movement and balancing of energy to meet demand also could help maximize resource use, said Michael Howard, president and CEO of the industry-backed Electric Power Research Institute.

“What we really have to do is to optimize the resources ... “to make sure that the system as a whole is resilient and also cybersecure and also constantly rebalances,” Howard said.